manganese deposits of cedar creek valley, frederick … · stone and the oriskany sandstone, both...

UNITED STATES DEPARTMENT OF THE INTERIOR Harold L. Ickes, Secretary

GEOLOGICAL SURVEY W. C. Mendenhall, Director

Bulletin 936-E

MANGANESE DEPOSITS OF CEDAR CREEK

VALLEY, FREDERICK AND SHENANDOAH

COUNTIES, VIRGINIA

BY

WATSON H. MONROE

Strategic Minerals Investigations, 1942

(Pages 111-141)

UNITED STATES

GOVERNMENT PRINTING OFFICE

WASHINGTON : 1942

For sale by the Superintendent of Documents, Washington, D. C. ....... Price 35 cents

CONTENTS

Page

Abstract................................................. IllIntroduction............................................. Ill

Geography............................................ 113Geology.................................................. 114

Stratigraphy......................................... 114Structure............................................. 115

Ore deposits............................................. 117History of mining and production..................... 117Minerals of the ore.................................. 118Types of deposits.................................... 118Relation of ore deposits to physiography and struc

ture ............................................... 120Economic possibilities............................... 120

Manganese mines and prospects............................ 122Nelson No. 2 prospect................................ 122.Nelson No. 1 prospect................................ 122Limestone Ridge, prospects............................ 122Moses Orndorff prospect.............................. 123Mineral Ridge mine................................... 123

History and production........................... 123Workings......................................... 124Geology.......................................... 125Manganese ore deposit............................ 126Mining and preparation of the ore................ 128

McCune prospect...................................... 128Brill prospect....................................... 128Godlove mine......................................... 129Bonnet Hill mine..................................... 130Rhesa A. Orndorff prospect........................... 132Mary Orndorff prospect............................... 132Prank Peer prospect.................................. 133James Orndorff prospect.............................. 133Cleve Peer prospect.................................. 134R. L. Orndorff prospect.............................. 134Unnamed prospect..................................... 134Ralph Orndorff prospect.............................. 135Capola Mountain mine................................. 135

History and production........................... 135Workings......................................... 136Geology.......................................... 137Manganese-ore deposit............................ 139

III

ILLUSTRATIONS

Page

Plate 12. Map of part of northern Virginia showinglocation of Cedar Creek Valley............... 114

13. Geologic map and sections of part of CedarCreek Valley, Va., showing location of man ganese mines and prospects............... In pocket

,,14. Geologic map of the Mineral Ridge mine......... 122r-15. Geologic map-of the Bonnet Hill and Godlove

mines........................................ 13016. Geologic map and sections of Capola Mountain,

Va....................................... In pocket

IV

By Watson H. Monroe

ABSTRACT

The Cedar Creek manganese mining district is in the south western part of Frederick County and the northwestern part of Shenandoah County, Virginia. The manganese ore consists chiefly of the oxides' pyrolusite and psilomelane, and forms replacement pockets and fracture fillings in the Oriskany sandstone and in residual sandy clay and chert derived from the New Scotland limestone. Both these formations are of Devonian age, and both form low ridges. The minable bodies have been deposited by ground water in the zone of weathering, and most of them lie above present ground-water level. The manganese-bearing forma tions, together with the older and younger formations exposed in Cedar Creek Valley, have been compressed into numerous folds, and at the southwestern end of the district one of these folds passes into a normal fault with a displacement of 1,000 feet or more.

Manganese ore has been mined in the valley since 1834, and about 15,000 tons of ore had been shipped from four mines before 1941. Most of the marketed manganese ore from Cedar Creek Val ley has been sold to the chemical and brick industries and only a minor part has been sold as metallurgical ore. Because ore for chemical and brick purposes has commanded a higher price than that generally paid for metallurgical ore, mining in the valley has to some extent been carried on during times of low prices for metallurgical ore.

The ratio of recoverable manganese concentrates to manga nese-bearing rock varies considerably, the maximum being about 1 ton of concentrates to 6 tons of crude ore and the minimum about 1 ton of concentrates to about 15 tons of crude ore. It is estimated that about 30,000 tons of manganese concentrates containing 40 percent or more of manganese will be recoverable in the proved mining areas in Cedar Creek Valley during times of high prices for manganese; and this tonnage of recoverable concentrates may be doubled by further exploration of the pres ent known ore bodies.

INTRODUCTION

A resurvey of the manganese deposits of western Virginia

with a view to evaluating available supplies was begun by the

111

112 STRATEGIC MINERALS INVESTIGATIONS, 1942

Geological Survey in the fail of 1940; and the mapping of the

manganiferous deposits in Cedar Creek Valley in Frederick and

Shenandoah Counties, Va., was assigned to the author. With the

generous permission of Arthur Sevan, State Geologist of Virgin!

Raymond S. Edmundson contributed his manuscript map of the

southwestern part of the Middletown quadrangle, which includes

all the Frederick County part of the manganese-bearing area in

Cedar Creek Valley, and a brief account of the stratigraphy of

that part of the quadrangle for incorporation in this report.

Mr. Edmundson also spent an additional week in the field in

October 1940, to adjust his mapping to the larger s'cale,

1:24,000, that was employed by the author in the field surveys

for the remainder of the Cedar Creek Valley.

As no satisfactory base map was available for the part of

the valley southwest of the Middletown quadrangle, a topographic

base was prepared from plane-table traverses that followed the

principal roads and extended to the manganese prospects of the

area, supplemented by form lines sketched from aerial photo

graphs obtained from the United States Forest Service. A

detailed map was made of Cap'ola Mountain. The final map, then,

embodies a combination of detailed surveys of the mining proper

ties, less accurate surveys of the principal roads and prospects,

and sketched form lines of the other topographic features,

Josiah Bridge, Charles Butts, and R. S. Edmundson spent a

few days in the field with the author in March 1941, for the

purpose of checking the stratigraphic sections of rocks that are

exposed at the various mines and prospects. In May 1941, H. D.

Miser accompanied the author on a two-day field trip during

which the ore deposits at Capola Mountain and at Mineral Ridge

were studied.

Messrs. Charles F. Nelson, of Strasburg, Va., J. Carson

Adkerson of Washington, D. C., Dennis Pickens of the American

Alloy Corporation, J. E. Cully of the Allied Manganese Corpora-

MANGANESE DEPOSITS OF CEDAR CREEK VALLEY, VA. 113

tion, and many citizens of Cedar Creek Valley have generously

given the author information about the history of mining and

manganese production in the district. Vincent A. Leonhardt and

Harry Peer ably assisted the author as- rodmen during the field

surveys.

Studies of the manganese deposits of the Cedar Creek Valley

were made in 1918 by G. W. Stose and Ho D. Miser, who also, in

1920, made plane-table surveys of Mineral Ridge, Frederick

County, and of Bonnet and Godlove Hills, Shenandoah County. The

results of their investigation of these deposits were pub

lished in 1922, and were freely utilized in preparing the

present report.

Geography

Cedar Creek Valley is in the northwestern part of Virginia,

between Little North Mountain on the southeast and Great North

and Paddys Mountains on the northwest (pi. 12). The surveyed

area (see pi. 13), about 10 miles long and 2 miles wide, covers

only the upper part of the valley, near Gravel Springs Church,

Frederick County, and Van Buren Furnace, Shenandoah County. Itsi

northern part lies about 7 miles northwest of Strasburg and the

southern part about the same distance northwest of Maurertown.

Graded roads connect the area with the paved Strasburg-Star

Tannery road, and a graded road crosses Little North Mountain

through Fetzer Gap to join the Valley Pike (U. S. Highway 11) at

a point between Woodstock and Maurertown. The part of the val

ley described in this report is sparsely settled, and most of it

away from the roads is included in the George Washington

National Forest

Cedar Creek flows northeastward through a basin, 21 miles

long and 1 to 6 miles wide, that lies between Little North and

I/ Stose, 0. W., and Miser, E. D., Manganese deposits of western Vir ginia: Virginia Oeol. Survey Bull. 23, pp. 57-gg, 1922.

114 STRATEGIC MINERALS .INVESTIGATIONS, 1942

Great North Mountains. The stream leaves the basin through a

gap in Little North Mountain 2^- miles northeast of Wheatfield,

and thence flows south to the North Pork of the Shenandoah River,

which it enters 2^ miles east of Strasburg.

The middle part of the basin is a broad, gently rolling low

land, into which Cedar Creek has cut an inner, narrow valley,

50 to 200 feet deep. The lowland rises gradually toward the

southwest from a little over 1,000 feet above sea level near

Gravel Springs to a little over 1,200 feet near Cedar Creek

Church, beyond which it is not recognizable. Between the low

land and Paddys Mountain is a belt of ridges with concordant

crests whose general level rises from about 1,500 feet at the

northeast to 1,800 feet at the southwest. It is on these ridges

that the manganese mines and prospects occur. A third topo

graphic surface is represented by the crests of Great North,

Paddys, and Little North Mountains, which attain altitudes of

2,500 to 3,000 feet.

GEOLOGY

2/Stratigraphy '

The manganese-bearing formations of southwestern Frederick

County and northern Shenandoah County are the New Scotland lime

stone and the Oriskany sandstone, both of'Devonian age. The

mapping of the area to the extent that was necessary for under

standing the structure involved the mapping not only of these

two formations but also of older and younger beds, all of which

are briefly described In the table on page 115.

On the geologic map (see pi. 13) the Tonoloway and Keyser

limestones are shown as a unit, because any attempt to map each

separately would require extensive faunal studies not justified

by the present program.

2] The section on stratigraphy is adapted from notes submitted "by Ray mond S. Edmundson of the Virginia Geological Survey.

UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY BULLETIN 936 PLATE 12

I 0 I SMilesContour interval 500 feet

MAP OF PART OF NORTHERN VIRGINIA SHOWING LOCATION OF CEDAR CREEK VALLEY

t

MANGANESE DEPOSITS OP CEDAR CREEK VALLEY, VA. 115

Sequence of rocks exposed in Cedar Creek Valley, Virginia

ThicknessQuaternary system: in feet

Alluvium and fan deposits:Heterogeneous mixture of cobbles, pebbles,

and silt................................... 0-20Devonian system:

Chemung, Brallier, and Romney formations:Thick bodies of shale and sandstone. <>........ 7,000

Oriskany sandstone:Coarse, ferruginous, fossiliferous, crumbly

sandstone, containing a few conglomeratic layers, particularly in the upper part; this is a resistant bed forming the crests of many ridges .............o.............. 50-100

New Scotland limestone:Medium-granular gray to dark-blue abundantly

fossiliferovis limestone, containing interbedded layers of chert; from 5 to 15 feet above the base of the limestone is a per sistent layer of more or less phosphatic sandstone from 2 to 5 feet thick; this limestone layer is resistant and forms many ridges.....o............o.................. 95-130

Keyser limestone:Medium-grained nodular limestone passing up ward into alternating granular and bluish- gray fine-grained limestone; top 5 to 10 feet consists of massive granular lime stone .................................... o. 170-220

Silurian system:Tonolway limestone:

Thin-bedded, finely laminated dark-gray lime- .stone, containing near top several thin granular layers like the overlying Keyser.. 250-275

Wills Creek shale:Yellow shale, earthy platy limestone, and

red shale and sandstone.................... 150Bloomsburg redbeds:

Bright red mudrock and sandstone............. 200McKenzie formation:

Yellow shale, containing a few layers of redshale...................................... 150

Clinton formation (Keefer sandstone member):Gray quartzitic thick-bedded sandstone, com posed of subangular to rounded quartz grains in a siliceous matrix............... 50

Structure

In harmony with the typical Appalachian pattern of linear,

plunging folds, the rocks underlying Cedar Creek Valley have

been folded into a compound syncline, of which Little North

Mountain forms the southeast limb and Paddys Mountain the north

west limb. The syncline follows roughly the course of Cedar

Creek from Capola Mountain to and beyond the northeastern

466068 O - 42 - 2


boundary of the area here mapped. (See pi. 13.) Paddys and

Little North Mountains owe their height to the resistance of

the Tuscarora quartzite (Silurian), which forms their crests.

Within the syncline younger formations of Silurian and Devonian

age are exposed; the youngest rocks in the syncline, namely,

the Romney shale and the Brallier and Chemung formations, are

exposed in its deeper northern part. The syncline is not a

simple fold, for the Intense folding, especially in the south

western part of the area, has crumpled the strata into a series

of narrow synclines and anticlines, which plunge into the valley

toward the northeast. At the southwestern end of the mapped

area there are many parallel folds, whereas at the northeastern

end there is only one anticline.

The ridges of Cedar Creek Valley are formed by the outcrop

ping edges of the hard strata upturned on the folds, while the

valleys are underlain by the softer intervening strata. Since

many of the- folds are of nearly the same height, the two manga

nese-bearing formations, the New Scotland limestone and the

Oriskany sandstone, as well as other formations, are repeated

several times at the surface. The dip gradually changes in

steepness along the strike, and the sides of some folds in the

southwestern part of the area have been compressed until they

are parallel. The strata are overturned in the anticline on the

southeast slope of Sugar Hill, so that here the Wills Creek

shale dips 75° SE. and rests on the younger Tonoloway limestone

(sec. F-P', pi. 13).

Of the two anticlines on the southeast side of the major

syncline, the northwestern one plunges beneath the floor of the

valley just southwest of the Fetzer Gap road and the other

plunges beneath the valley at a place about three-quarters of a

mile farther northeast, where the outcrop of the Oriskany sand-


stone forms a prominent horseshoe-shaped hill. The southeastern

limb of this anticline is broken by a normal fault, which

increases in throw toward the southwest. At the Fetzer Gap road,

where the plane of the fault dips 84° toward the southeast, the

lower part of the Bloomsburg redbeds, or possibly the upper part

of the McKenzie formation, on the northwest side of the fault is

brought into contact with the Onondaga shale member of the Rom-

ney on the southeast side. The displacement at that locality is

thus about 1,000 feet (sec. F-F', pi. 13): Still farther south

west along the crest of the anticline, the Clinton formation and

the underlying Tuscarora quartzite form the top of Tea Mountain,

but, as no outcrops of the Onondaga were seen in the valley to

the southeast, the magnitude of the displacement there is not

known. At several places along the fault there are large verti

cal blocks of sandstone resembling the Oriskany, which appar

ently have been dragged into their present position by the move

ment in the fault zone. Southeast of the fault the strata of

the Oriskany and New Scotland are slightly overturned, and have

reverse dips of 65° and 70°, respectively, toward the southeast.

ORE DEPOSITS

History of mining and production. The history of manganese

mining in Cedar Creek Valley before 1920 is summarized as fol-3/

lows by Stose and Miser ,

The manganese deposits of western Virginia have been worked at times since 1834 and have yielded .both manganese and manganiferous iron ores. The earliest mine to be worked was the Min eral Ridg6 mine, in Frederick County. It is said to have been worked for many years before the Civil War, beginning in 1834, and for many years after the war. * * * The Bonnet Hill mine in Shenandoah County was worked in 1848 * * * but no ore from it was marketed at that time. The Godlove mine in Shenandoah County was first worked about 75 years ago # * # and it was again worked* * * 35 to 40 years ago. * * * The Capola Mountain mine was worked extensively -many years ago, large amounts of manganese ore being shipped before the Civil War. * * #

During the period from 1915 to November 1918, when there was a £reat demand for domestic manganese ores, for which high

Stoae, G. W., and Miser, H. D., op. cit., pp. U3-U5.


prices were paid, manganese mining in western Virginia, as else where in the United States, was greatly stimulated. Most of the above-mentioned mines * * « were opened, and numerous new local ities were prospected for manganese ore. In November 1918, when the armistice with Germany was signed, the demand for domestic ores practically ceased, except for the filling of unexpired wartime contracts, and work at most of the mines and prospects stopped.

The Mineral Ridge mine was worked at times between 1920 and

1932 and was reopened in 1940. The Gapola Mountain mine was

operated in 1937 and 1938, and was further prospected in 1940,

but no work was being done at the mine at the time of the

author's last visit to the area in May 1941. So far as known

little mining or prospecting was done elsewhere in the valley

between 1920 and 1940.

Prior to 1920, it appears that less than 4,500 tons of man-4/ ganese ore had been shipped from Cedar Creek Valley. ' Since

1920 it is estimated that between 10,500 and 11,000 tons have

been shipped. The total production of manganese ore for the

valley before 1941 has thus been about 15,000 tons.

Minerals of the ore.--The manganese minerals found In Cedar

Creek Valley are all oxides, and four of them that are common

are pyrolusite, wad, psilomelane, and manganite, named in the

order of their abundance. Psilomelane is not so common here as

recognized at all the mines in the valley.

At the Mineral Ridge mine a few quartz crystals and a small

quantity of the phosphate mineral, wavellite are associated with

the manganese deposit, and at nearly all the mines and prospects

hydrous iron oxide is associated with the manganese oxides.

Types of deposits. The manganese deposits in Cedar Creek

Valley are replacement pockets and fracture fillings, irregular

in size and shape. Some of the deposits occur in sandy clay and

chert derived from weathering of the New Scotland limestone,

others in porous, friable sandstone and conglomerate of the

U/ Stose, G. W., and Miser, H. D., op. cit., pp. UU, 59, 75, 81.


Oriskany sandstone Manganese deposits in the weathered resid

uum of the New Scotland limestone are found at the Mineral Ridge

and Bonnet Hill mines and at the Limestone Ridge, Rhesa A. Orn

dorff, Mary Orndorff, Prank Peer, James Orndorff, R. L. Orndorff,

and Ralph Orndorff prospects. The deposits in the Oriskany

sandstone are found at the Godlove and Capola Mountain mines and

the McCune, Brill, and Mary Orndorff prospects.

Of the deposits in the residuum of the New Scotland lime

stone only that at the Mineral Ridge mine could be studied in

detail, but the others are more or less similar. At the Mineral

Ridge mine the manganese oxides, mostly pyrolusite, are concen

trated along bedding and joint planes, where they form films and

relatively narrow lenses in which the oxides have partly or

entirely replaced the sandy clay and chert.

The manganese deposit of the Capola Mountain mine is typical

of the deposits in which the oxides are obtained from highly

weathered Oriskany sandstone. There the oxides, mostly pyrolu

site and wad, are found in veinlets, in lenses filling voids

between bedding planes and fracture surfaces, and in somewhat

larger masses along bedding and fracture surfaces, where the

oxides have replaced the sandstone. In general the oxides have

replaced only the finer-grained material; in the conglomeratic

beds, for example, the sand grains have been replaced by manga

nese oxide while the quartz pebbles have not.

The manganese oxides in the several mines and many prospects

of Cedar Creek Valley have been concentrated and deposited in

the present ore bodies by ground water, which presumably

obtained its manganese content from the rock during weathering.

Although the source of the manganese is not known it may have

been disseminated manganese carbonate in the New Scotland lime

stone or the Oriskany sandstone. Only in the zone of weathering

are the oxides concentrated into mlnable ore bodies, and most of

these ore bodies lie above the present ground-water level.

^20 STRATEGIC MINERALS INVESTIGATIONS, 1942

Relation of ore deposits to physiography and structure, All

the mines and ore-bearing prospects in Cedar Creek Valley are

near the crests of low hills, from 200 to 400 feet above the

lowland of the valley, with the exception of the Rhesa A. Orn-

dorff prospect, which is at water level on Trout Run.

Manganese oxides are found only at those places where the

strata have been shattered by jointing, close folding, and

minute faulting. Only in the channels thus formed, it appears,

could the manganese-bearing solutions circulate freely. Close

folding, such as that observed at Mineral Ridge and Capola Moun

tain, caused more shattering than the more open folding observed

elsewhere, as on'Big Hill. Structure has also determined, to

some extent, in what formations the manganese oxides were depos

ited. In certain areas where, as at the Mineral Ridge mines,

the dips were prevailingly gentle, the downward-seeping ground

water passed through the Orlskany sandstone and deposited the

oxides in porous, weathered New Scotland limestone; but where,

as at the Capola Mountain mine, the dips are nearly vertical,

the path of least resistance was entirely within the Oriskany

sandstone, and the oxides were precipitated in that rock.

Economic possibilities. Ore has been marketed from only

four properties in the valley: the Mineral Ridge mine, the Bon

net Hill mine, the Godlove mine, and the Capola Mountain mine.

At the time of the author's last visit to Cedar Creek Valley, in

May 1941, none of the properties was being operated, but the

American Alloy Corporation was planning to resume operations at

the Mineral Ridge mine.

Only a small part of the marketed manganese ore from Cedar

Creek Valley has been used for metallurgical purposes. All of

the ore from the Godlove mine and most of that from the Bonnet

Hill and Mineral Ridge mines has been used for chemical purposes

in the manufacture of dry batteries and of flint glass and

for making bricks.


The marketed manganese ore from Cedar Creek Valley that has

been consumed by the chemical and brick industries has commanded

a higher price than metallurgical ore; and, because most of the

marketed ore from the valley has been used in .those industries,

it has been possible to do some mining in this area even when

prices for metallurgical ore were low.

The amount of recoverable manganese in Cedar Creek Valley

depends in part upon the proportion of marketable-manganese con

centrates obtainable from the ore as mined. This proportion was

estimated by comparing the weights of various lots of ore that

have been mined hitherto with the weights of the manganese con

centrates obtained from them. T.he maximum ratio was found to be

about 1 ton of concentrates to 6 tons of crude ore and the mini

mum about 1 ton of concentrates to 15 .tons of crude ore. Prom

these figures, combined with rough calculations of the volume

and tenor of ore still in the ground, it is estimated that about

30,000 tons of manganese concentrates containing 40 percent or

more of manganese is recoverable in the proved mining areas in

Cedar Creek Valley during times of high prices for manganese ore;

and it is also estimated that this tonnage of recoverable con

centrates could perhaps be doubled by further exploration of the

present known ore bodies. The largest known ore body in the

valley is at the Mineral Ridge mine, where additional develop

ment work may reveal extensions of the present known ore body.

Additional prospecting might reveal new deposits or extensions

of known deposits on Limestone Ridge, on Fox Ridge (see pi,, 15),

on Bonnet Hill, on the various hills comprising Big Hill, on

Capola Mountain east of the present workings, and on the hill

due east of Capola Mountain. At all of these places more or

less promising prospects have been opened in the past.


MANGANESE MINES AND PROSPECTS

Mo3t of the manganese mines and prospects in Cedar Creek

Valley have been described by Stose and Miser, 'and in. the fol

lowing pages a brief summary of their findings is given. These

are supplemented by descriptions of new developments made since

the publication of their report and of a few prospects that,

though opened many years ago, were first studied during the

recent field work. The number in parentheses following the name

of each mine, or prospect corresponds to that showing the loca

tion of the property on the map (plo 13).

6/ Nelson No* 2 prospect (1)

The Nelson No. 2 prospect is a tunnel driven northwestward

into the Oriskany sandstone on the southeast flank of the Sarah

Orndorff Ridge, at an altitude of about 1,150 feet. The tunnel

stopped in sandstone and did not encounter any manganese oxide.

7/ Nelson No. 1 prospect (2)

The Nelson No. 1 prospect is a northwesterly trending tun

nel, 132 feet long, on the southeast slope of Stave Mill Ridge

(Mcllwee Ridge), at an altitude of about 1,320 feet. The tun

nel entered the Oriskany sandstone and was not driven far

enough to reach the New Scotland limestone.

8/ Limestone Ridge prospects (3)

The pits on Limestone Ridge' exposed brecciated chert

cemented and in part replaced by manganese oxide inclosed in

dark wad soil. No manganese ore in commercial quantity was

discovered in the pits. The altitude of the two southern pits

5/ Stose, G. W., and Miser, H. D., op. cit., pp. 57-SS. b^ After idem, p. 71.

Idem.Idem, p. 72.

UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY BULLETIN 936 PLATE 14

X.c>o' . ' ,

EXPLANATION

From plane-table survey in July 1920 by H. D. Miser, published in Virginia Geol. Survey Bull.23. Modified in March 1941 by W. H.Monroe

Strike and dip of beds

Shaft

>Z=3

Tunnel

*Limestone quarry

~7=> Open cut

Dump

Contour interval 50 feet Datum is mean sea /evel

GEOLOGIC MAP OF THE MINERAL RIDGE MINE


is about 1,600 feet; that of the northern pit is about 1,560

feet.

9/ Moses Orndorff prospect (4)

No prospecting has been done on this property on Mcllwee9/

Ridge since Stose and Miser -'visited the 12-foot shaft in the

Oriskany sandstone at this place, which is about 1,160 feet '

above sea level. The shaft revealed sandy manganese oxide in a

vein l|r inches thick near the surface but the quantity is far

too small to be commercial.

10/ Mineral Ridge mine (5)

The Mineral Ridge mine is on Mineral Ridge, also known as

Manganese Ridge, in Cedar Creek Valley, 2-| miles north of Zepp

and 8 miles west-northwest of Strasburg. Mineral Ridge is on

the northwest side of the valley and extends northeastward from

Cold Spring Run (also known as Hollow House Run) to Paddys Run,

a distance of 4,800 feet. (See pi. 14.) It attains an altitude

of 1,440 feet above sea level and rises about 300 feet above the

runs at either end. Its crest is narrow and straight and its

slopes are steep. At its eastern base is a gently rolling area

with an altitude of about 1,100 to 1,200 feet above sea level.

History and production.--Intermittent mining of manganese

ore on Mineral Ridge dates as far back as 1834, and the total

production of the mine before 1920 was about 3,500 tons of ore.

On April 1, 1920, the mine was leased from Charles F. Nelson

by N. H. Mannakee and associates who operated under the trade

name of Hy-Grade Manganese Co. This company continued to oper

ate, removing ore mainly from the No. 6 tunnel and from drifts

to the northeast and southwest, until January 16, 1929. In

October 1929 the property was leased by the Hy-Grade Manganese

Stose, G. I., and Miser, H. D., op. cit., pp. 70-71. Condensed from idea, pp. 57-69.

466068 O - 42 - 3


Production & Sales Corporation, which operated it until December

1932. The mine remained idle from 1932 until September 1940,

when it was bought from Mr. Nelson by the American Alloy Corpor

ation. During the period of operation by the Hy-Grade Manganese

Co. beginning in 1920 it shipped about 6,440 tons of ore,

i!/according to the owner, Charles F. Nelson. The successor com

pany, the Hy-Grade Manganese Production & Sales Corporation, is

said by Mr. Nelson to have shipped about 3,545 tons. Thus the

total production of the mine before July 1941, the date of the«»

first shipment by the American Alloy Corporation, was about

13,500 tons of ore.

Workings, There are workings along the crest of the ridge

for a distance of 2,500 feet, but most of them are at and near

the middle part of the ridge. They consist of open cuts, pits,

shafts, and tunnels. In 1920 only two tunnels were accessible.

The higher of these was at an altitude of 1,393 feet above sea

level, or 40 feet below the highest point on the crest of the

ridge, and extended west-northwestward into the ridge a distance

of 150 feet. Prom its northwest end two parallel drifts, 15

feet apart, had been driven 100 feet to the northeast, and two

such drifts .had been run 250 feet to the southwest. Crosscuts

connected the parallel drifts at several places, and stopes had

been made above the drifts. The No, 6 tunnel was at an altitude

of 1,312 feet above sea level, or 120 feet below the highest

point on the crest of the ridge, and extended 268 feet west-

northwestward. At a distance of 163 feet from the portal a

drift had been run 84 feet to the northeast and another drift

had been run 114 feet to the southwest. Small stopes had been

made above both drifts.

The Hy-Grade Manganese Co. cut another tunnel (No. 8) 80

feet below the No. 6 tunnel described above. The No. 8 tunnel,

ll/ Oral communication.


at an altitude of 1,233 feet, penetrated the clay and chert

residuum of the New Scotland limestone and continued into lime

stone. It passed through the weathered strata that contained

manganese in the higher workings, but in this tunnel these

strata contain only stains of manganese oxides. The tunnel has

since caved in and is now inaccessible.

The Hy-Grade Manganese Production & Sales Corporation

enlarged the small 'open cuts at the west and joined them into

one, from which it obtained the bulk of its ore. In 1941 the

cut was about 850 feet long, 50 to 75 feet wide, and 30 to 50

feet deep.

Geology. A section of the rocks exposed in No. 8 tunnel was

measured in 1928 by M. I. Goldman. His notes indicate that

40 feet of shattered Oriskany sandstone, veined with red clay,

is underlain by 82 feet of more or less sandy chert and clay,

residual from the New Scotland limestone. This material is

underlain by a 2|-foot bed of sandstone containing phosphatic

nodules and manganese stains. The sandstone is underlain by

13 feet of cherty clay, which merges downward into 20 to 40 feet

of clay derived from limestone, probably the Keyse'r. Wavellite

was observed on chert about 7 feet above the phosphatic sand

stone.

The New Scotland limestone on the ridge is weathered to

cherty clay to the depth of the lowest tunnel, which is at an

altitude of 1,233 feet, or more than 200 feet below the crest of

the ridgeo Although the cherty layers have a general dip of 35°

to 40° to the southeast, the individual layers are bent into

small folds, or wrinkles, so that the dips in a single exposure

may range from nearly horizontal to nearly vertical. At the

southwestern end of the open cut the beds have been compressed

into a small recumbent anticline. These minor structural fea

tures have caused intense fracturing of the strata.


The New Scotland limestone is underlain on the northwest

side of the ridge by a few feet of coarsely granular limestone12/ that, according to Bridge and Butts, 'may be equivalent to" the

Coeymans limestone. As the fossils are not entirely diagnostic

this unit is included with the Keyser limestone, which thus

includes about 220 feet of coarse-grained dark-gray fossilifer-

ous limestone, thin-bedded knotty limestone, and shaly limestone.

Underlying the Keyser near the foot of the ridge is thin-

bedded and laminated, more or less shaly limestone of the Tonol-

oway, and on the southeast slope of the ridge there are a few

exposures of the Onondaga shale member of the Romney shale.

Manganese ore deposit. The deposit of manganese ore occurs

in the lower part of the sandy and cherty clay that is residual

from the New Scotland limestone. Most of the ore is immediately

above the phosphatic sandstone bed near the base of the New

Scotland, but some is found just below this bed. The ore is

irregularly distributed through a zone from about 15 to 30 feet

thick. The ore body has the same attitude as the chert beds; it

strikes northeast, parallel to the trend of the ridge, and its

dip apparently averages between 20° and 25° SE. at the mine but

increases to 40° or more both northeast and southwest of the

mine. The workings show that ore occurs for a total distance of

2,500 feet along the ridge and extends down the dip into the

hill below the level of No. 6 tunnel but not as deep as No. 8

tunnel. Thus the depth from the surface to the bottom of the

ore body is between 130 and 200 feet vertically or between 260

and 400 feet along the dip of the ore zone.

The manganese oxides at Mineral Ridge include pyrolusite,

wad, manganite, and psilomelane, of which pyrolusite is the most

common. The proportion of pyrolusite increases with depth to

the level of No. 6 tunnel, but in No. 8 tunnel only wad was

found. The oxides occur in seams parallel to the bedding of the

12/ Bridge, Josiah, and Butts, Charles, oral communication.


chert and clay, in veinlets that cut the chert, and in small

pockets replacing chert and clay. Associated with the manganese

oxides at some places are brown iron oxide, a few small quartz

crystals, and a very little wavellite.

The ratio of manganese oxides to oxide-bearing chert and

clay in the ore zone differs from place to place, and little is

known concerning it.

Analyses of shipments of manganese for chemical purposes are

not available. Analyses of 20 carload lots of manganese ore

that was shipped before 1921 for metallurgical purposes are

given in the accompanying table, adapted from the table on

page 66 of the report by Stose and Miser. They show the follow

ing range in composition: Manganese 39.53 to 52.67 percent,

average about 46 percent; iron 0.85 to 7.10 percent; phosphorus

0.22 to 0.42 percent; silica 0.85 to 10.63 percent; and alumina

1.62 and 9.20 percent (recorded in two analyses).

The manganese ore marketed after 192Q is reported to have

averaged about 45 percent manganese.

Analyses of manganese ore shipped before 1921 from Mineral Ridge mine

1....2....3.... 4.... 5.... 6..., 7.... 8.... g

10.... 11.... 1 913.... 14....15....16.... 17.... 18... o 19.... 20....

Manganese (Mn)

48.6444.76 52.67 48.37 49.18 50.28 48.03 45.61 45.5943.47 39.53 42.1642.77 44.5041.0842.02 48.14 51.97 48.36 48.93

Iron (Fe)

3.90 .85

3.25 1.30 3.25 4.50 5.57 6.184.10 7.10 4.085.14

4.98 4.03 1.76 2.65 1.50

Phosphorus (P)

0.296 .227 .226 .284 .257 .261.23 AI-)

.27

.23

.29

.23

.22

.24

Baryta (BaO)

0

o

o

o

0

e!87

o

0

*

Silica(sio2 )

7.10 1.08 7.05 2.05 5.43 5.55 5.78 .85

9.51 9.60

1/3.148.06 8.02

10.6310.54 6.13 3.22 3.41 4.40

Alumina (A1203 )

9.20

l'.62

o

Moisture

10.251.25 1.57 1.58 5.46 1.60 7.65 5.71

6.20 o

9.06 12.323.005.70

if Includes alumina.


Mining and preparation of the ore. Before 1915 the mine was

worked by means of shafts, open cuts, and tunnels. The ore was

hand-picked to free it from chert and clay, and some is said to

have been washed and ground in a mill on Paddys Run. Prom 1915

until 1921 the ore was all mined from a large open cut.

The Hy-Grade Manganese Co. built a mill on the bank of

Paddys Run at the northeastern end of Mineral Ridge This mill

was abandoned and a new one was built by the Hy-Grade Manganese

Production & Sales Corporation in 1929 on the southeast slope of

Mineral Ridge just northeast of the portals of tunnels No. 6 and

No. 8 (pi. 14). This mill was equipped with a ball mill, a

Fehrenwald sizer, 12 jigs, 4 sand tables, and 3 slime tables.

In 1940, when the American Alloy Corporation bought the

property, most of this equipment was utilized in a new plant,

equipped with crushers, jigs, tables, and classifiers, which was

erected at the same site as its predecessor. The corporation is

planning to use steam shovels in an open cut. The manganese ore

is hauled in trucks to Strasburg, where it is shipped by rail.

13/ McCune prospect (6)

An inclined tunnel 20 feet long, at an altitude of 1,380

feet, and a small pit were opened about 35 years ago on the west

slope and near the crest of Pox Ridge. Both of them were made

in sandstone beds of the Oriskanv_, and the tunnel followed one

or more of the beds. They revealed some thin veins of manganese

ore, but the quantity of it was small, only 200 pounds being

obtained.

14/ Brill prospect (7)

13/ After Stoae, G. W., and Miser, H. D.. op. cit., pp. 73-?U. Idem, p. 73-


which carry some manganese oxide. The prospect has produced

about 2 tons of pyrolusite ore which forms thin veins and pock

ets in the fractured sandstone. The ore contains much silica in

the form of sand grains and quartz pebbles, whose presence indi

cates that the manganese oxide has replaced pebbly sandstone.

Godlove'mine (8)

The Godlove mine is 1^ miles northwest of Zepp on the north

east end of Godlove Hill, which is just south of Shell Run and

between Bonnet Hill and Paddys Mountain. The hill is about a

quarter of a mile wide and half a mile long, and attains an

altitude of 1,440 feet above sea level.

The mine was first worked about 100 years ago and was oper

ated intermittently until 1915. It was operated more inten

sively from 1915 to 1920., when three to five carloads of ore

used for chemical purposes was shipped. There has been only

intermittent prospecting since.

The workings consist of several shafts and two tunnels, one

at an altitude of 1,364 feet and the other at 1,327 feet. The

upper tunnel extended southward 185 feet, and drifts and

inclines aggregating about 150 feet branch from it. The lower

tunnel was about 300 feet long and trended a few degrees east of

south. The portals of both tunnels had caved in by 1940, but

some of the shafts could still be entered. The manganese ore

deposit is concentrated in a bed of clay 4 or 5 feet thick and

in fractured sandstone at the base of the Oriskany sandstone on

the southeast side of the Godlove Hill syncline.

The extent of the ore deposit has not been determined fully,

but all the workings were concentrated in a north-south belt

400 feet long and 200 feet wide. The manganese oxides consist

of pyrolusite with a small amount of psilomelane 0 Mining was

Modified after Stose, G. W., and Mlaer, H. D. f op. clt., pp. 81-S5.


done by hand in shafts and tunnels, and all the marketed ore was

hand-picked.

16/ Bonnet Hill mine (9)

The Bonnet Hill mine is 2 miles southwest of the Mineral

Ridge mine and 1 mile northwest of Zepp. The mine is on Bonnet

Hill, a low northeastward-trending ridge on the northwest side

of Cedar Creek Valley. The hill extends from Wymer Run to Shell

Run, a distance of 5,000 feet, and attains an altitude of 1,510

feet above sea level. (See pi. 15.)

The mine was first worked in 1848 and was last worked in

February 1920. The total reported production of the mine, most

of which was made during several years prior to 1920, has been

about 12 carloads of ore of which 8 were chemical ore and 4 met

allurgical ore.

The mine workings are on and near the crest of the ridge at

about equal distances from the north and south ends. They

include several prospect pits, largely in surface material

6 feet deep with soft ore at the base, several shafts 30 to

40 feet deep, short irregular drifts running from the shafts,

an open cut, and three tunnels. All the shafts and tunnels were

caved in 1940. Two of the tunnels are on the east slope, one at

an altitude of 1,470 feet and the other at an altitude of 1,415

feet, or 85 feet below the crest. This lower tunnel is 300 feet

long and trends west-northwest. The other tunnel is on the west

slope.

As at the Mineral Ridge mine the manganese ore deposit is in

the lower part of sandy, cherty clay, residual from the New

Scotland limestone, which dips steeply toward the southeast.

This residual chert forms the crest of the ridge at the mine and

for several hundred feet northeast and southwest of the mine.

Because of settling during weathering of the limestone, the dips

!§/ Modified after Stose, G. W., and Miser, H. D., op. cit., pp. 7^-80.

UNITED STATES DEPARTMENT OF THE INTERIOR

GEOLOGICAL SURVEY BULLETIN 936 PLATE 15

\ \

Keyser limestone Dkand "Tonoloway h

Strike and dip of beds

o Shaft

Tunnels«£5

Sink hole or pit'/M>*

Dump

From plane-table survey in July 1920 by H.D. Miserpublished in Virginia G-eol.Survey Bull. 23

100 0in,i i

1.000 Feeti i ii

Contour interval 50 feet Datum is mean sea level

GEOLOGIC MAP OF THE BONNET HILL AND GODLOVE MINES


in the chert are somewhat irregular; beds have been observed

that dip as much as 45° SE., but the average dip at the mine is

probably about 30° SE.

On the southeast slope of the ridge, and reaching the crest

at the southwest and northeast ends of the ridge, is porous,

friable, pebbly sandstone dipping steeply toward the southeast

and containing molds of fossil shells characteristic of the

Oriskany sandstone. The Oriskany is overlain on the lower

slopes of the northeast side of the hill by greenish-brown shale

of the Onondaga member of the Romney shale.

Just northwest of the crest of the ridge and on the road

that extends northeast from the mine along the crest of the

ridge are many exposures of coarsely granular fossiliferous

limestone, knotty limestone, and shaly limestone of the Keyser.

The Tonoloway limestone Is exposed at the crest of the anticline,

just south of the saddle between Bonnet and Godlove Hills.IT/

Concerning the manganese ore deposit, Stose and Miser

say:

Although the ore is irregularly distributed through the chert and clay, the general dip and strike of the ore body are the same as those of the chert and clay. The strike is there fore to the northeast and the dip is probably about 30° SE. The workings show that it /Fhe ore/ occurs at or near the surface within a belt about 60 feet wide and 400 feet long, trending northeastward from the old tunnel that is on the west slope. The shafts southwest of the tunnel * # # failed to discover ore. * * * A cut « « » near the Strosnider Spring /at the northeast end of the hill/ it it it penetrated yellow rocky sandy loam and no manganese minerals were found.

The shafts at the mine followed workable ore to a depth of as much as 40 feet below the surface and the new /Tower/ tunnel revealed ore at an elevation of about 95 feet below the highest point on the crest of the ridge. # * *

The ore-bearing zone penetrated by the shafts consists of chert, clay, and ore, and lies parallel with the bedding of the chert and clay. Where It was seen by the writers in one of the shafts it was several feet thick. Mr. Adkerson says it averages 8 feet thick in the shafts. The zone was just being penetrated in the new /Tower/ tunnel when work was discontinued- there. At places the pure ore makes up by weight more than half of the zone and some of the larger pockets yielded as much as 6,000 Ibs. of pure ore. The ore has replaced the chert and clay. * * # The ore consists of pyrolusite and psilomelane, mostly the former.

Ij7 Stose, G. ff., and Miser, H. D., op. cit., p. 78.


Fourteen analyses included by Stose and Miser 'show the

composition of the ore from the Bonnet Hill mine. Ten analyses

of soft ore showed 55.93 to 59.53 percent manganese, 0.10 to

1.27 percent iron, 0.199 percent phosphorus (1 analysis), and

0.97 and 5.90 percent silica (2 analyses). Three analyses of

hard ore showed 49.58 to 52,38 percent manganese, 0.39 to 1.87

percent iron, 0.078 to 0.141 percent phosphorus, and 11.86 to

15.75 percent silica.

19/ Rhesa A. Orndorff prospect (10)

The Rhesa A. Orndorff prospect is an old tunnel at an alti

tude of 1,186 feet, on the north side of Trout Run and 1-|- miles

southwest of Zepp. The tunnel follows the strike of the miner

alized zone 60 feet, and a lower parallel drift, reached by a

slope 35 feet long down the dip of the bed, is said to go in

200 feet. Seventy tons of manganese ore is said to have been

removed from the tunnel and placed on the dump at the edge of

the run. Iron and manganese oxides occur in chert beds 1 to 2

feet thick separated by thin sandy clay beds near the middle of

the New Scotland limestone. At the entrance the oxides are

chiefly those of iron but in depth they are reported to be

chiefly manganese and to fill crevices and seams in the chert

and partly replace it. As determined by an examination of frag

ments on the dump, the manganese oxide is pyrolusite, in part

intimately mixed with some iron oxide. No analyses of the man

ganese material are available.

Mary Orndorff prospect (11)

The Mary Orndorff prospect is on the ridge east of the Sugar

Hill road, 1.3 miles west-southwest of Cedar Creek Church. The

prospect consists of two openings, a shaft, said to be 16 feet

IS/ Stoee, 0. W., and Miser, H. D., op. clt., p. SO. 15/ After idem, pp. S5-S6.

MANGANESE DEPOSITS OP CEDAR CREEK VALLEY, VA. . 133

deep, on the northwest flank of the ridge, and a nearby open cut

on the crest of the ridge. The shaft is in the New Scotland

limestone and the cut is in the adjoining Oriskany sandstone.

The dump beside the cut shows a small quantity of manganese

oxide, mostly as a cement and stain in the sandstone. The alti

tude of the ridge at the cut is 1,474 feet.

Frank Peer prospect (12)

The Prank-Peer prospect is 0.4 mile southwest of the Mary

Orndorff prospect and is on the northwest slope of the same

ridge. It consists of a tunnel and a shaft that probably were

opened before 1915. The tunnel starts in the lower part of the

residual chert of the New Scotland limestone and trends south

eastward toward the shaft. The mouth of the shaft, which is

1,414- feet above sea level, is about 20 feet northwest of and

below the contact of 'the New Scotland and Oriskany formations.

No ore was found on the dump during a visit in '1941, but the

fragments of chert are stained with manganese oxide and some

fragments show partial replacement by psilomelane.

James Orndorff prospect (13)

The James Orndorff prospect is on the next ridge east of the

Prank Peer prospect and 0.4 mile northwest of Van Buren Furnace

post office. The prospect consists of a tunnel, at an altitude

of 1,390 feet, on the southwest side of a small transecting hol

low, and a series of shafts .extending up the nose of the ridge

toward the southwest to an altitude of 1,460 feet. At the time

of the visit in 1941 all the shafts and the tunnel, which may

have connected with them, had caved in. The prospects are in

the upper part of the chert and clay residuum of the New Scot

land limestone, about 30 feet stratigraphically below the con

tact with the Oriskany sandstone. Although there is some


psilomelane in the chert on the dumps, only a little ore is said

to have "been found in the openings.

Cleve Peer prospect (14)

The Cleve Peer prospect, which was opened in 1940 by J. E.

Cully, consists of a tunnel, at an altitude of 1,346 feet, on

the southwest side of a low ridge, a quarter of a mile northwest

of Cedar Creek and almost a mile west of Van Buren Furnace post

office. The tunnel enters the top of the Oriskany sandstone and

extends northwestward for a distance of 25 feet in the sandstone.

It shows a few small pockets of slightly manganiferous sandstone

and a little limonitic sandstone but no sizable body of ore.

R. L. Orndorff prospect (15)

The R. L. Orndorff prospect is on the northwest slope of Big

Hill, at an altitude of 1,367 feet and about three-quarters of

a mile southwest of Cedar Creek Church. At this locality a

shaft, which has caved until it is now only about 10 feet deep,

penetrated the residual chert of the New Scotland limestone,

probably near the middle of the formation,, Chert fragments on

the dump are stained with manganese oxide. Another shaft is

said to have been dug nearby, but it was not seen.

Unnamed prospect (16)

An unnamed prospect on a hill east of the Fetzer Gap road

and a third of a mile south of Cedar Creek consists of a tunnel,

now caved, on the northwest slope of the hill and a shaft on the

southeast slope, both at an altitude of about 1,320 feet.

Nothing is known of the history of this prospect. Both the tun

nel and the shaft are in the residual chert of the New Scotland

limestone. The dumps contain a little manganese-stained chert.


Ralph Orndorff prospect (17)

The Ralph Orndorff prospect is on the southern crest of the

double hill east of Capola Mountain and south of Van Buren Fur

nace post office. The two ridges are projecting ledges of Oris-

kany sandstone, and are separated in the low saddle by a syncli

nal belt of greenish-brown shale of the Onondaga member of the

Romney shale. The prospect consists of a tunnel near the crest

of the west nose of the ridge and of a shaft about 40 feet deep

on the crest, whose altitude is 1,602 feet. The shaft is open

but the tunnel has caved. Both are in the lower part of the New

Scotland limestone which here dips steeply to the northwest.

The dumps contain some manganese oxide and much manganese-

stained chert.\

Capola Mountain mine (18)

Capola Mountain, a ridge trending westward, is just south of

Cedar Creek and from 3jjt to 5 miles southwest of Zepp. The moun

tain is about 6,600 feet long and 1,900 feet wide, and its high

est point is 1,800 feet above sea level. The backbone of the

mountain is a long narrow ridge, paralleled by a discontinuous

ridge from 200 to 400 feet to the north. The altitude of the

valley floor of Cedar Creek is about 1,320 feet near old Van

Buren Furnace and about 1,220 feet at the east end of the moun

tain.

History and production. The Capola Mountain mine was oper

ated about 1080 by the Van Buren Furnace Co., which is said to

have shipped some manganese ore.

In 1937 M. C. Smithson and associates, operating as Southern

Ores, Inc., excavated the large open cut at the western end of

the mountain (No. 11 on pi. 16) and obtained ore from it and the

tunnels, which trend east from the open cut. This company built

a mill at the western end of the cut and operated until 1938,


when the mill burned down. Mr. Smithson says that many of the

records were lost in the fire but he believes that the company

marketed between 500 and 1,000 tons of ore in 1937 and 1938.

This agrees well with a local report that the company shipped

10 or 12 carloads of ore. The ore was hauled- in trucks to Wood-

stock and shipped on the Southern Railway.

In 1940 John E» Cully and associates, known as the Allied

Manganese Corporation, obtained from the United States Forest

Service, a lease on the western end of the mountain, and opened

a cut (No. 9) into an old drift formerly reached only by a shaft

(No. 8). The corporation had done considerable prospecting by

the spring of 1941, but no ore had been shipped.

Workings. The manganese workings on Capola Mountain are on

the west end of the mountain, at altitudes rarfging from 1,480

to 1,700 feet above sea levelo They consist of pits, shafts,

tunnels, and an open cut, all in an area 1,000 feet long and

300 feet wide. The principal source of marketed ore has been

an open cut (No. 11) 30Q feet long, from 12 to 40 feet wide, and

from 20 to 40 feet deep. The cut is nearly straight with a

trend of N. 70° E. The floor of the cut has an altitude of

1,557 feet at its west end or entrance and is there about

12 feet wide; it is horizontal to a point about 70 feet to the

east, where it has a width of 15 to 25 feet, then rises to 1,576

feet. At the east end of the 1,576-foot level is the portal of

a tunnel, which will be described below. Beyond this level the

cut reaches a maximum width of 40 feet and rises by irregular

steps to the top or east end which has an altitude of 1,650 feet.

The portal of a second tunnel is on the north side of the cut,

30 feet west of the east end and at an altitude of 1,620 feet.

Essentially all of the ore obtained by Southern Ores, Inc., was

mined from the open cut and the tunnel at the 1,620 foot levelo

When the Capola Mountain mine was visited in May 1941, four

tunnels were entered; the portals of two others had caved. The


tunnel at the 1,576-foot level in the open cut (No. 11) extends

N. 70° E. along the line of the cut for 155 feet to an ore chute

from the higher tunnel, from which it extends N. 22° E. in this

direction for 30 feet to the face. The tunnel at the 1,620-foot

level runs parallel to the cut for about 40 feet to the top of

the ore chute, where a stope rises about 10 feet and a drift

continues toward the east, but this higher part was not entered.

The portal (No. 9) opening into the drift of the Allied Man

ganese Corporation is just north of the crest or the ridge at an

altitude of 1,649 feet. A small open cut leads to the portal

and from it a crosscut extends southeastward to a drift, in part

a stope, which extends parallel to the crest of the ridge, or

about N. 70° E., for 105 feet. The altitude of the bottom of

the stope is 1,633 feet. A shaft (No. 8) was the former

entrance to this drift and stope.

The fourth tunnel (No. 12), entered in 1941, extends north

ward from the south slope of the ridge at an altitude of 1,620

feet. It is 220 feet long and has two short drifts branching

off 160 feet north of the portal. One rises slightly for

15 feet toward the east, then crosscuts 20 feet toward the south,

and finally goes 15 feet farther toward the east. The total

rise in this drift above the tunnel level is about 15 feet. The

other branch goes only 8 feet toward the south. An irregular

stope rises about 30 feet along the bedding 200 feet north of

the portal.

Many other workings are shown on the map (see pi. 16), but

they had all caved at the time of the writer's visit.

Geology. The sequence of rocks exposed on Capola Mountain

is shown on the following page.

The chief structural feature of Capola Mountain is a closely

compressed syncline, the axis of which lies just north of the

crest of the mountain. A steep-sided anticline extends along

the north slope of the mountain. The structure is complicated


by small subsidiary folds that raise the Oriskany sandstone to

the surface in the belt of the Onondaga shale member of the Rom-

ney along the axis of the syncline. The accompanying sections

(see pi. 16) show the approximate attitude of the rocks, but

some of the close folding at the west end.of the mountain is not

shown. One of these close folds is well exposed in the Allied

Manganese cut (No. 9 on pi. 16), where the Onondaga shale has

been folded down into the Oriskany sandstone in a synclinal belt

only about a foot across.

Sequence of rocks exposed on Capola Mountain, Virginia

ThicknessOnondaga shale member of the Romney shale: in feet

Yellow to greenish-brown hackly shale, much ofit impregnated with limonite................... 100

Oriskany sandstone:Coarse, ferruginous, fossiliferous crumbly sand

stone containing in upper part abundant quartz pebbles; contains at places in upper part pock ets and seams of manganese oxide; makes ridges on mountaino................................... 120

New Scotland limestone:Dark-gray more or less granular and fossiliferous

limestone containing interbedded layers of chert.......................................... 120

Keyser limestone:Massive granular and shaly limestone............. 220

Tonoloway limestone:Thin-bedded and shaly limestone, generally nearlyblack on fresh surface......................... 240

Just north of the mine workings is a somewhat larger syn

cline which encloses a body of Onondaga shale at the Allied Man

ganese cut (No. 9) and at the west end of the large open cut

(No. 11). Between these two places, however, the syncline is

not deep enough to include any Onondaga, and the underlying

Oriskany sandstone is here exposed along the synclinal axis.

The accompanying anticline to the north of this syncline again

brings Oriskany to the surface at the two extremities'. The dip

of the south flank of this anticline, 55° toward the south, was

observed only at the Allied Manganese mine. No dips were

obtained on the north flank of the anticline, for the Oriskany

there is broken into large blocks. There may be a fault along


this flank, but no fault is shown on the map or sections because

of'lack of evidence. North of this anticline is the axis <jf the

main syncline.

The structure is similarly complicated farther east along

the crest of the mountain, where, as shown on the map (see

pi. 16) and'section C-C r , other small syriclines and anticlines

are present. The tight folding here has shattered the Oriskany

sandstone and formed the numerous joints and small faults along

which the manganese oxides have been concentrated. In the open

cut (No. 11) four main sets of fractures are exposed. The main

set strikes N. 30° E. and dips 33° SE., another set dips north,

a third dips southwest, and the fourth is vertical and strikes

easto Some of these fractures have highly polished slickensides

that indicate slight movement.

Manganese ore deposit. The ore body revealed in the open

cut and tunnels (No. 11) occurs in a bed of pebbly sandstone

12 to 25 feet thick, near the top of the Oriskany sandstone.

The ore body dips toward the north with the bedding of the sand

stone, whose inclination increases from 65° in the higher work

ings, at an altitude of 1,670 feet, to 70° in the bottom of the

open cut at an altitude of 1,560 feet. The manganese oxides of

the ore body are irregularly distributed in veinlets, in frac

ture fillings, and in irregular masses where they have replaced

the sandstone. The most abundant oxide is pyrolusite; manganlte

and wad also are present.

Near the mouth of the open cut (No. 11) the footwall con

tains relatively little mineral, but the hanging wall or north

wall contains highly fractured sandstone with considerable pyro

lusite and some iron oxide. The lower part of this cut is from

11 to 15 feet wide and here all the minable 'ore has apparently

been removed.

At the next level of the open cut (altitude 1,576 feet) the

ore body is a continuation of that from the lower level, though


here a small quantity of manganese oxide occurs in pebbly sand

stone in the south or footwall. The 155-foot tunnel that

extends eastward from this cut contains only a little iron oxide.

Higher levels of the open cut reveal an upward continuation of

the ore body, but here the ore-bearing zone becomes a little

wider. At the portal of the upper tunnel, at an altitude of

1,620 feet, the ore zone is 18 feet wide. The tunnel at this

level contains little ore, and moat of that obtained from this

opening apparently came from the higher drift that was connected

with it at its east end by means of a raise..

The lower part of the Oriskany sandstone, just below and

south of the ore body just described, also contains manganese

oxides but the veinlets are too small to permit mining. From

the bottom of the open cut at an altitude of 1,557 feet to the

foot of the mountain (altitude 1,420 feet) the fractured Oris

kany sandstone contains veinlets of manganese and iron oxides in

which iron oxide predominates.

The drift south of opening No. 9 contains veinlets and

lenses of pyrolusite and wad, up to 6 inches wide and 4 feet

long, in sandstone. Many of the larger veins are along bedding

planes of the sandstone. The ore-bearing sandstone in this tun

nel, which is partly a stope, reaches a thickness of 3 feet, and

in places it contains many lenses of pyrolusite and wad. Some

crude ore removed in excavating the tunnel and now on the dump

consists chiefly of pyrolusite through which quartz grains and

pebbles are distributed. Only a part of this material is lumpy

and solid. Similar material was formerly hoisted from the drift

through the shaft designated No. 8 on the map and still lies on

the dump beside the shaft.

The crosscutting tunnel driven from the south slope of the

mountain at an altitude of 1,620 feet penetrated the sandstone

throughout its entire length except for the first 25 feet, which

is in sandy clay and chert derived from the weathered New Scot-


land limestone. Manganese and iron oxides are exposed in the

northern 70 feet of this tunnel, but the manganese oxide is

mostly wad, with a little pyrolusite.

Prom the data given above and shown on the map, the devel

oped and mined ore body apparently extended eastward from the

mouth of the open cut for a distance of about 800 feet and was

from 3 to 18 feet wide, becoming narrower with depth. Sandstone

containing ore extends downward from the surface to an average

depth of less than 40 feet. All the minable ore in the open cut

(No. 11) appears to have been removed, and, unless the ore body

is found to extend farther east, at least half of the minable

ore in the deposit has been mined.

O